JTextFields and with my school project

Question

For my chemistry class my teacher told me i could earn extra credit by making some sort of chemistry related program. I thought that this was a good idea, because i am in AP computer science after all. This is my code so far, but i cant get it to display the string i want it to, even after i press the enter key. Any help would be great. Thanks!

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.*;

    public class window extends JPanel implements KeyListener {

        private static final long serialVersionUID = 1L;
        private JTextField textBox;
        private String textInput;

        public window() {
        textInput = "";
        textBox = new JTextField("Enter symbol here:", 30);
        this.add(textBox);
    }

    public void paint(Graphics g) {
        super.paint(g);
        g.setColor(Color.CYAN);
        g.setFont(new Font("", Font.BOLD, 20));
        g.drawString("Enter element symbol in text box above.", 110, 50);
        g.drawString(textInput, 100, 100);
    }

    public void keyPressed(KeyEvent e) {
        int code = e.getKeyCode();
        if (code == KeyEvent.VK_ENTER) {
            textInput = textBox.getText();
        }
        repaint();
    }

    public void keyReleased(KeyEvent e) {

    }

    public void keyTyped(KeyEvent e) {

    }
}



import java.awt.Color;
import javax.swing.JFrame;

    public class elementRunner {

        public static void main(String[] args) {
            window panel = new window();
        JFrame frame = new JFrame("Element project ~ By: Harsh Patel");
        frame.setBounds(100, 100, 600, 600);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setResizable(false);
        panel.setBackground(Color.RED);
        frame.setVisible(true);
        frame.addKeyListener(panel);
        frame.add(panel);
    }
}

Answer 1

The problem is you are setting the listener to the JPanel , if you set it to the JTextField it works. I attach the code below, however, maybe JLabels would be helpful. I mean, it's easier, more structured etc. But you will have to learn how layouts work. Anyway, this is how it looks to me:

ElementRunner.java (uppercase Element).

public class ElementRunner {

    public static void main(String[] args) {
        MyWindow panel = new MyWindow();
        panel.setBackground(Color.RED);

        JFrame frame = new JFrame("Element project ~ By: Harsh Patel");
        frame.setBounds(100, 100, 600, 600);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setResizable(false);
        frame.add(panel);
        frame.setVisible(true);

    }
}

MyWindow.java (Window was too generic, this way we know it's yours, uppercase like Element)

public class MyWindow extends JPanel implements KeyListener {

    private static final long serialVersionUID = 1L;
    private JTextField textBox;
    private String textInput;

    public MyWindow() {
        textInput = "";
        textBox = new JTextField("Enter symbol here:", 30);
        textBox.addKeyListener(this); // This line adds the listener to the TextField
        this.add(textBox);
    }

    public void paint(Graphics g) {
        super.paint(g);
        g.setColor(Color.CYAN);
        g.drawString("Enter element symbol in text box above.", 110, 50);
        g.drawString(textInput, 100, 100);
    }

    public void keyPressed(KeyEvent e) {
        int code = e.getKeyCode();
        if (code == KeyEvent.VK_ENTER) {
            textInput = textBox.getText();
        }
        repaint();
    }

    public void keyReleased(KeyEvent e) { }

    public void keyTyped(KeyEvent e) { }
}